This disclosure relates generally to automotive applications and, more particularly, to applications requiring high-resolution non-contact torque sensing.
Current engine sensing technology has no reliable, cost-effective, or direct means for measuring the torque output of an engine. The vehicle driver inputs a torque demand via the throttle pedal, and based upon this, fuel quantity and injection timing are looked up in a table that has been conservatively calibrated. The oxygen sensor provides an average feedback to the engine controller based on the multiple cylinders connected to the exhaust pipe. Based upon the fuel injection rate, injection timing, and the air/fuel ratio, the expected engine torque output may be calculated. The actual torque, however, may be different due to mixture preparation variation, unbalanced cylinders, or incomplete combustion.
High-resolution torque sensing will allow feedback of each cylinder's torque output, allowing the next cycle of combustion to be optimized on the fly leading to the maximum torque output of an engine. In addition, this direct feedback will improve fuel efficiency by allowing on-the-fly spark timing and fuel injection timing changes, as well as allow the engine controller to take advantage of the combustion properties of alternative and higher-octane fuels. Misfire detection, cylinder to cylinder balancing, drivability improvements, and individual cylinder tuning can be done with a direct feedback torque sensor to improve efficiency over the life of the engine.